1. Field of the Invention
The present invention relates to method and apparatus for processing an INCOMING CALLING LINE IDENTIFICATION (ICLID) data message, and more particularly, to a method and apparatus for causing certain functions to take place, (such as not activating the telephone ringer or ringing it with a different ring pattern) when the ICLID data message is determined to be a predetermined message (such as a "PRIVATE" message).
2. Description of the Prior Art
Many telephone companies are now offering an ICLID service wherein an ICLID signal, indicative of the source of the incoming call, is transmitted to the receiver between the ring signals. The user subscribing to the ICLID service would then have the caller's identification signal (most typically the caller's telephone number) displayed on a display unit adjacent to or integral with the telephone. The ICLID subscriber then knows the source of the call even before answering.
A problem with the above-described ICLID service is that many communities and jurisdictions may enact legislation to allow the initiator of an ICLID call to block the outgoing identification signal. Therefore, ICLID service providers may offer their subscribers a feature whereby the call initiator can selectively block or transmit the ICLID message indicating his or her telephone number. This selective calling number blocking feature may be provided on a blanket basis or on a per call basis. That is, customers may be offered the option of having the passage of their telephone numbers suppressed on all outgoing calls or on a per call basis. In the latter case they would have to prefix their outgoing calls with a special code to activate suppression of transmittal of their telephone numbers. In either case, the ICLID signalling protocol will be set up to send the message "PRIVATE" to the ICLID subscriber when they receive a call from a calling party which has blocked transmittal of his or her own phone number.
An ICLID subscriber receiving a "PRIVATE" message then has the option of answering the call or just letting the phone continue to ring until the calling party decides to terminate the call, if the receiving phone or ICLID unit has the capability of making it known that this call is from a party that has chosen to withhold his or her number. The present invention proposes a method and apparatus for giving the ICLID subscriber more options than just letting the telephone continue to ring when a "PRIVATE" ICLID signal is received.
Generally, the technology incorporated in the basic ICLID service is described in U.S. Pat. No. 4,551,581 (Doughty), which discloses a method and apparatus for sending a data message (ICLID signal) to a selected station during a silent interval between ringing signals. Also, U.S. Pat. No. 4,582,956 (Doughty) explains a method and apparatus for displaying, at a selected station, special service information (ICLID identification signal) during the silent interval between ringing signals. Both of these patents are incorporated herein by reference.